mcelwain



l. McELWAIN.4

VARIABLE SPEED MECHANISM.

APPLICATION FILED uov.23. 1915.

l 1 95,052 Patented Aug. 15, 1916.

6 SHEETS-SHEET l.

1. McELWAIN.

VARIABLE SPEED MECHANISM.

APPLICATION man nov.23. 1.915.

1 l 95,052 Patented Aug. 15, 1916.

6 SHEETS-SHEET 2.

WITNESSES INVENTOR Wam@ I www, da@ mw@ wmmm J. McELWAlN.

VARIABLE SPEED MECHANISM.

APPLlcAnoN FILED Nov.23. 1915.

1 ,1 95,052. Patented Aug. 15, 1916.

6 SHEETS-SHEET 3- WITNESSES INVENTOR I. MCELWAIN.

VARIABLE SPEED MECHANISM.

APPLICATION FILED NOV.23. 1915.

Patented Aug. 15, 1916.

6 SHEETS-SHEET 4.

INVENTOR J. MCELWAN.

VARIABLE SPEED MECHANISM.

APPucATloN FILED nov.23. 1515.

1 1 95,052.v Patented Aug. 15, 1916.

e SHEETS-SHEET 5.

WITNESSES a A um.

v1. MCELWMN.

VARIABLE SPEED MECHANISM. APPLlcArloN FILED N0v.23. 1915.

1 1 95,052. Patented Ang. 15, 1916.

` I 6 SHEETS-SHEET 6.

J7'f 6@ l C l y@ 22awl'rNEssEs STATES` PATENT OFFICE.-

JAM-ES MOELWAIN, OF WHEELING, vWEST VIRGINIA, ASSIGiNOR T0 SAMUEL P.NORTON ANID ARTHUR G. HUBBARD,l TBUSTEES, OF WHEELING, WEST VIRGINIA. i

VARIABLEQSPEED MECHANISM.

Specification of Letters Patent. Patented Allg, 15, 191.6.v

Application filed November-23, 1915. Serial No. 62,961.

To all whom it may concern.' Y

Be it known that I, JAMES MCELWAIN, a citizen of the United States,residing at Wheeling, in the county of Ohio and State of lVest Virginia,have invented a new and useful Improvement in Variable- SpeedMechanisms, of which the following is a full, clear, and exactdescription, reference being had to the accompanying drawings, formlngpart of this specication, in which- Figure 1 is a longitudinal sectlonthrough one form of apparatus built in accordance with my invention.Fig. 1a is a view of a portion of Fig. 1, on a larger scale. Figs-2, 3and 4 are transverse sections on the lmes II II, III-III and IV-IV,respectlvely, of Fig. 1. Fig. 5 is a detailed sectional view on the lineV-V of Fig. 1. Figs. 6 and 7 are sectional views on the lines VI-VI andVII-VII, respectively, of Fig. 1. 8 is a diagram of the device shown inFig. l. Fig. 9 is a longitudinal view through. a modiiied'form ofgearing, and Fig. 10 is a sectional detail view on the line X-X of. Fig.3.

This invention relates to an improvement in variable speed mechanism,and is designed to provide an eiiicient device of this character inwhich the power shaft is normally driven at a constant speed, while thespeed of the driven shaft will vary in accordance with the load.

The object of my invention is to provide a device of this character inwhich the driven shaft can be connected to the driving shaft while thesame is running atnormal speed without shock or jar.

The precise nature of my invention will be best understood by referenceto the accompanying drawings which will now be described, it beingpremised, however, that various changes may be made in the details ofconstruction and the generalarrangement of the parts without departing,from the spirit and scope of my invention, as defined-in the appendedclaims.

In the drawings, I have shown a device which is. more particularlyadapted for run,`

ning automobiles and in which the reference character A designates thecasing or housing, which is made up of the cylindrical member 2 and theheads 3 and 4. This housing is provided with lugs 5 for securing it tothe chassis of the automobile.

6 designates a driving shaft which .is connected to the .motor in anydesired manner,

so that it will be lrotated at approximately \a constant speed. Thisshaft 6 1s journaled in bearings in the head 3 and one end thereof1s\prov1ded with a gear 7 having beveled teethIk 8 and sp'ur teeth 9,which form a portion of a differential train hereinafter described.Rotatably mounted in bearings in the head 4 is the driven shaftjlO whichis 1n line with the shaft 6 and is arranged to be driven by a sun. andplanetary gear system, sothat the speed of the shaft 10 iscontrolled bythe load.

A B designates a housing which is rotatably mounted on central hubs onthe heads 3 and 4 which hubs surround the shafts 6 and 10, respectively.This frame is built up of the end membersll and 12, a disk member 13 andthe body member 14 which are secured together by means of bolts, so thatthey allrotate 1n unison. The disk member 13 is provided with bearin sat its central portion for thegear wheels g on the driving shaft and oneend of a gear end of 'this gear frame ed on the central hub on the head4, the arrangement being such that the frame C is adapted to rotatewithin the frame B. This frame C comprises the end members 15 and 1 6, aspider 17 and a body member 18, which are connected together by means ofbolts so as to form a unitary structure. Rotatably mountedvinfbearingsin the end member 11 of the frame B are three crank shafts 19each of which is provided with a beveled C is rotatably mountgear 20which mesh with the teeth 8 on the gear wheel 7. Mounted within the diskmember 13 and in line with the crank shafts 19 are .pump cylinders 21which are provided with pistons 22 connected to cranks 23 on the crankshafts 19 through the medium of pitmen 24. Each of these cylinders isprovided with an intake check valve 25 and the outlet check valve 26which communicates with chambers opening into the ends of the cylinders,as shown in Fig. 10.

frame C. Theother check valves 26 to 'the chamber 27, when moving in theopposite direction.

Rotatably mounted on` spindles 30 in the disk members 11 and 14 are spurgears 31 which mesh with the teeth 9 on the gear 7, as well as with theteeth 32 on the Aend member 15 of the frame C. Rotatably mounted inbearings in the spider17 are three crank shafts 33, each of which isprovided with a bevel gear 34, which mesh with the bevel gear 35 securedto the shaft 10.

36 are cylinders which are formed in the body member 18 of the frame C,there being three of these cylinders within this frame, and each isprovided with apiston 36 which is connected with a crank 37 by means ofa pitman 3S on its respective crank shaft 33. The end heads of each ofthese cylinders are provided with exhaust ports 39 and inlet ports 40.

41 is a pressure chamber in the member C, formed between the body memberand the end member 15, which is constantly in com munication with thepressure chamber 27 in the disk member 13, by means of a port 42. Thisport 42 extends through a central tube formed integral with the diskmember 13 or secured thereto in any manner. Surrounding this tube memberand within an annular flange' on the' end member 15 is a packing member43 which is adapted to maintain a tight joint between the frames B andC. Within the chamber 41 are pins 44 and-mounted therein are valves 45for controlling the admission and exhaust of air to and from thecylinders 36. Each of these valves is provided with a port 45a to opencommunication between the port 40 and the exhaust port 39 and they arealso provided with a cut-away portion to admit pressure to theirrespective cylinders through the port 40 from the chamber 41.

46 are pinions formed on the stems of the valves which are in mesh withthe gear wheel 47, which is mounted on the end of a stem rotatablymounted within the central portion of the frame C, and is connected toone end of the driven shaft 10 by means of a tongue and grooveconnection.

The valves controlling admission of pressure to the motor cylinders 36,and the exhaust therefrom are set so that the movement of the motorswill actuate the gears 34, to cause the frame to rozate clockwise.-

The pressure chamber 41 is provided with a relief valve 48 which is heldto its seat by a compression spring 48a in a casing 49, the tension ofthe spring being adjusted by the hollow nut 50 adjustably mounted in theend of the casing 49; and 51 is a hand-hole covei for a hand-hole in thebody portion 2 of the frame A, through which access can be i had toadjust the tension of the spring 48".

52 is a stem slidably mounted within the driving shaft 6, which isprovided at one end with a control valve 53 which is normally held toits seat by a spring 54, and which valve'is adapted to relieve thepres-l sure in the chambers 27 and 41 for the pur- .pose hereinafterdescribed. The end of the stem 52 is in line of movement of the pin 55in a slot 56 extending through the shaft 6, and is connected to agrooved disk 57 slidably mounted on the shaft 6.

l 58 is a lever pivoted to projections extending from the head 3 and isprovided with a yoke 59 at one end having pins which engage the groovein the disk 57 to shift the disk and thereby open the valve 53.

As before described, the shaft 6 is constantly driven in a clockwisedirection at approximately a constant speed by the engine on the car,and the shaft 10 will be driven through the medium of the differentialgearing in a similar direction, the speed of the shaft being controlledby the load thereon. As the only clutch driving connections between thetwo frames B and C are the pumps and motors, it will readily beunderstood that, when the valve 52 is open, there will not be anydriving connection between the gear wheel 7 on the shaft 6 and the gearwheel 35 on the shaft 10, so that when this valve is open the engineshaft will not be operatively connected to the driven shaft. The ratioof the gears throughout the differential gearing is three to one, so'thateach revolution o f the frame B with relation to the shaft 6 willreciprocate each pump piston 22 three times, while the `motor piston 36will be reciprocated three times for each revolution of the frame C withrelation to the shaft 10. The valve 45 will be actuated in timedrelation with the movement of the frame C and the shaft 10, and as thepinions 46 are one-third the size of the gear wheel 47, each valve willbe rotated three times for each revolution of the frame C with relationto the shaft 10.

I will now generally describe the operation of the device when the caris on level ground, or the load on the shaft 10 is such that the drivingpower of shaft 6 is suiicient to drive shaft 10 at the same speed asshaft 6.

Assuming that the engine is running so as to rotate the shaft 6 in aclockwise direction when coupled thereto by any suitable device and itis desired to rotate shaft 10. The op- I erator first opens valve 53 andconnects the shaft 6 to the engine shaft and thereby cause the shaft 6to rotate clockwise and as there is no connection between frames B andC, due to the valve 53 being open, the frame B will be rotatedcounter-clockwise by the gears 31, without affecting the frame C or theshaft 10, the gears 31 running idly in the teeth 9 of the gear 7. Thevalve 53 is then closed, which causes the pumps to build up pressure inthe chambers 27 and 41. This pressure, the counter-clockwise movement ofthe frame B is gradually decreased, until it becomes stationary. As thespeed of the frame C further increases, the frame B will be rotatedclockwise at a gradually increasing speed until the speed thereof andthe speed of the frame C are equal to the speed of the shaft 6, at whichtime .all the parts will rotate as a'unit, the frame C being rotated bythe action of the gears 31--on the gear teeth 9 and 32. At this time thepumps and motors will be inactive, with the 'exception that they formthe clutching means between the driving and driven members. Theclockwisemovement of the shaft 6 will rotate the frame B in a counter-clockwisedirection through the medium of the gears 31 meshing with teeth 9 and32. As the frame B is rotated the pinions 20 will be rotated through themedium of the teeth 8 which will actuate the pump pistons 22 and therebybuild up a pressure within the chambers 27 and 41. This pressure will,in turn, actuate the motor pistons 36a which will rotate the pinions 34in a direction to movethe frame C clockwise.

If the car is run onl level ground andthe power required to drive theshaft 10 at a speed equal to the speed of the shaft 6 is not greaterthan the power of the engine at this speed, the speed of the shaft 10will gradually be increased through the medium of the pumps and motorsuntil the shaftlO rotates at the speed of the engine shaft. The frames Band C, together with all of the mechanism 100 pounds, and the speed ofthe drivenv connected thereto will now rotate in unison with the twoshafts. If the load increases to an extent that the power required torotate the shaft 10 at the speed of the engine shaft is greater than thepower of the engine, the speed of the shaft 10 will gradually decreaserelative to the shaft 6 as the load increases.

Assuming that under normal conditions the driving shaft is run at 1000revolutions per minute and is capable of lifting a load of 1000 poundsat this speed, and that at this time the pressure between the pumpcylinders and the motor cylinders is 50 pounds:

under these conditions the entire mechanism will revolve as a unit aboutthe axes of the driving` and driven shafts. If the load should beincreased to 2000 pounds, it will be assumed that the pressure. betweenthe pumps andthe engine will be increased to shaft will be reduced to500 revolutions per minute.

The action of the motors upon the'gears 34 is in a direction to increasethe speed of frame-C. When this occurs the gears have a the shaft 10relatively to thelspeed of the I differential action so that the framesB and.'

C- may be rotated -at relatively diferent speeds, although under theoriginal assumptions'the shaft. 6 andthe .gear 7 are runnlng at aconstant speed. It, thereforeffollows that-the power' which is generatedby the pumps is transmitted to the motors and there utilized to assistintaking care of the increased load on the shaft 10; vand that the speedof the latter will thus automatically adjust itself tovariations inload. It will be furtherunderstood from the foregoing description thatif the load conditions are` such that the pumps and motors are -mutuallylocked against action, the pressure in the motors being equal to that inthe pumps; yand that in this condition the pumps and motors serve merelyas clutches for effecting the driving connections between the drivingand driven sides of the system. Just as soon, however, as the speed ofthe shaft 10 changes relatively to that of the shaft 6, the pumps andmotors are set into operation; and in the lcase of increased load themotors are nage effective to assist in taking care of said oa f 'If thisdriving mechanism is used in connection with automobiles it is essentialthat the shaft connected to the driving mechanism of the automobile canbe driven either go theright or to the left. I have, thereore,

mobile shaft 60. Fixedly connected to the end of the shaft 10 is a gearwheel 61, and slidably mounted on' the shaft 60 is a gear connected areversing mechanism with .the shaft 10 which in turn drivesthe autowheel62 havlng external teeth 63 and in- Y ternal teeth- 64. The internalteeth 64 are arrangedto engage the teeth of the wheel 61 when the wheelis in the position shown in Fig. 1 of the drawings, so as to drive theshaft 60 in a clockwise direction when'the wheels 62 and 61 areconnected to each other. v

Rotatably mounted in bearings in the head 4'and a frame 65 is a shortshaft 66 which is provided with a gear wheel 66a and a pinion 67. Thegear wheel 66a is normally in engagement with the gear wheel 68 whichmeshes with the gear wheel 61 and when the gear wheelv 62 is movedlongitudinally along the shaft 60 so that the teeth 63 mesh with thegear wheel 67, the shaft 60 will be rotated counter-clockwise. The gear61 is slidably mounted on a spline 68a seated in gears shown in theAother figures.

""and adapted to rotate about the aXis thereof,

ferential driving mechanism will not be connected with the shaft 60.

In Fig. 9 I have illustrated a modified form of differential gear inwhich I have applied the same reference characters with the letters aaiiixed, and in which I have shownl spur gears instead of the beveled Inthis constructionI have not illustrated the connections between the pumpcylinders 21 and the motor cylinder 36a.

The advantages of my invention result from the provision of a variablespeed transf mission gearing connecting a driving shaft and a drivenshaft 1n connectlon with the pump and motor system which are arrangedyto vary the speed of the driven shaft with relation to the speed of thedriving shaft in accordance with the load 'on the, driven shaft.

I claim:

1. Variable speed transmission gearing, comprising a driving shaft, adriven shaft, differential gearing connecting 'the two shafts, a pumpmounted on the driving shaft and adapted to rotate about the axisthereof, a motor mounted on the driven shaft and pressure transmittingconnections b etween the pump and the motor; substantially as described.

2. Variable speed transmission gearing, comprising a driving shaft, adriven shaft, diiferential gearing connecting the two shafts, a pumpmounted on the driving shaft and adapted to rotate about the axisthereof, a motor mounted on the driven shaft and adapted to rotate aboutthe axis thereof, and pressure transmitting connections between Vthepump and the motor, the pump and motor forming a variable clutchconnection between the differential gear elements and the driving anddriven shafts respectively; substantially as described.

3. Variable speed transmission gearing, comprising a driving shaft, adriven shaft, differential gearing connecting the two shafts, a pumpconnected to the driving shaft, a motor connected to the driven shaft,and pressurev transmitting connections between the pump and the motor,together with valve mechanism for the motor controlled by the rotationof the driven shaft; substantially as described.

4. Variable speedtransmission gearing, comprising a driving shaft, adriven shaft, dierential gearing connecting the two shafts, a pumpconnected to the driving shaft, a motor connected to the driven shaft,pressure transmitting connections between the pump and motor, and arelief valve in said connections; substantially as described.

5. Variable speed transmission gearing, comprising a driving shaft, adriven shaft, diiferential gearing connecting the two shafts, a pumpconnected to the driving shaft, a motor connected to the driven shaft,pressure transmitting connections between the pump and motor, and acontrol valve in said connections for permitting pressure .to escape tothe atmosphere; substantially as described.

6. Variable speed transmission gearing, comprising a driving shaft, adriving gear, two sets of planetary gears engaging the Adriving gear, apump system operated by one'set of the planetary gears, a driven gearactuated bythe other set of planetary gears, a driven shaft, a sun andplanetary gear \connection between ifthe last named gear Wheel and thedriven shaft, a motor system actuated by the last named -planetarygears, and pressure transmitting connections between the pump system andthe motor system; substantially as described. "i"

7. Variable speed` transmission gearing, comprising a driving shaft, adriven shaft, aV gear connected to the driving shaft, a frame rotatablymounted relative to the driving and driven shafts, two se'ts ofplanetary gears engaging the gear connected to the driving shaft, a pumpsystem carried by said frame and connected to one set of the planetarygears, a second frame rotatably mounted about the axes of the shafts, adriven gear connected to said second frame, a sun and planetary gearconnection be-v tween the second frame and the driven shaft, a motorsystem connected to the second frame, actuating connections between saidmotors and the last named planetary gears, and pressure transmittingconnections between the pump system and the motor system; substantiallyas described.

8. Variable speed transmission gearing, comprising a driving shaft, adriven shaft, a gear connected to the driving shaft, a frame rotatablymounted relative to the driving and driven shafts, two sets of planetarygears engaging the gear connected to the driving shaft, a pump systemcarried by said frame and connected to one set of the planetary gears, asecond frame rotatably mounted about the axes gof the shafts, a drivengear connected to said second frame, a sun and planetary gear connectionbetween the second frame and the driven shaft, a motor system connectedto the second frame,vactuating connections between said motors and thelast named planetary gears, and pressure transmitting connectionsbetween the pump system and the motor system, together with acontrolling valve in said connections for permitting the pressure fromthe pump system to pass to the atmosphere; substantially as described.

9. Variable speed transmission gearing, comprising a driving shaft, adriven shaft, a gear connected to the-driving shaft, a frame rotatablymounted relative to the driving and driven shafts, two sets of planetarygears engaging the gear connected to the driving shaft, a pump systemcarried by said frame and connected to one set of the planetary gears, asecond frame rotatably mounted about the axes of the shafts, a drivengear connected to said second frame, a sun and planetary gear connectionbetween the second frame and the driven shaft, a motor system connectedto the second frame, actuating connections between said motors and thelast named planetary gears,

' and pressure transmitting connections between the pump system and themotor system, a valve system for the motors carried by the second frame,together with actuating 15 connections between said valve system and thedriven shaft for actuating the valves in timed relation; substantiallyas described.

In testimony whereof, I have hereunto set

